According to our reseller, this is a limited time promotion for 2 months.
I'm unsure if it is going to be rolled out globally, or if it is just limited to Australia.
This is basically equivalent to Autodesk giving you a free copy of Autodesk® 3ds Max® Design to play with.
Here is the only catch - if you accept this free upgrade, your subscription cost will increase. In our case, it will be an additional $375 (ex GST) per license per year. In real terms, I guess it will take quite a few years of paying this increased subscription to actually 'break even' with how much it would have cost to buy 3ds Max outright.